Portable Electronic Apparatus

1. A portable electronic apparatus comprising: a housing including a front surface and a back surface opposite to the front surface, the housing having a longer side in the first direction and a shorter side in a second direction crossing the first direction; a touch panel arranged on the front surface, an acceleration sensor that detects an orientation of the housing; and a touch detector on the front surface, wherein the back surface includes a back edge area near one edge of the back surface and a back main area excluding the back edge area, a first width, which is between the back edge area and the front surface in a third direction vertical to the front surface, is wider than a second width, which is between the back main area and the front surface in the third direction, the front surface includes a front edge area near one edge of the front surface and a front main area excluding the front edge area, the front edge area including a first front-edge area and a second front-edge area arranged in the first direction, the touch detector detects a touch operation at least on the first front-edge area and the second front-edge area, when the acceleration sensor detects that the first front-edge area is above the second front-edge area in the third direction, a predetermined function is assigned according to the operation in the first front-edge area, and when the acceleration sensor detects that the second front-edge area is above the first front-edge area in the third direction, the predetermined function is assigned according to the operation in the second front-edge area.

2. The portable electronic apparatus according to claim 1 , wherein the first width at the widest point is wider than the second width by a value equal to or greater than 4 mm.

3. The portable electronic apparatus according to claim 1 , wherein the first width at the widest point is wider than the second width by a value equal to or less than 6 mm.

4. The portable electronic apparatus according to claim 1 , wherein a length, which is from an edge of the front edge area at a center side of the front surface, around the side surface, and to the back first edge, is equal to or less than 80 mm.

5. The portable electronic apparatus according to claim 1 , wherein when the acceleration sensor detects that the first front-edge area is above the second front-edge area in the third direction, a menu is displayed in the first front-edge area, and an image is displayed in the front main area such that an upper side of a text displayed in the front main area is upper in the third direction, and when the acceleration sensor detects that the second front-edge area is above the first front-edge area in the third direction, a menu is displayed in the second front-edge area, and an image is displayed in the front main area such that an upper side of a text displayed in the front main area is upper in the third direction.